MXPA02000690A - Module for connection and testing of high frequency transmission lines. - Google Patents

Abstract

Module for connection and testing of high frequency transmission lines, characterized in that the module includes an electrically conductive shield (preferably metallic) connected to ground, which covers one side of the module sufficiently to act as a barrier against inductive effects between two or more such modules when they are placed adjacent to each other (for example in an arrangement of such modules in a connection box) with the shield between them.

Description

MODULE FOR CONNECTION AND TESTING OF HIGH FREQUENCY TRANSMISSION LINES This invention relates to a module for connection and testing of transmission lines at high frequencies, ie frequencies of approximately 100 megahertz and above. The increasing use of telephone lines for data transmission makes it necessary to operate with incredibly high frequencies, in order to obtain wider bandwidths. However, not all components originally designated for telephone service can provide an acceptable data service with performance levels required by high frequency transmissions. In fact, when operating at high frequencies, there is an accentuation of any disturbances in the transmissions and reductions in signal strength, generally in direct proportion to the increasing frequency. Those undesirable frequency effects include: a) Attenuation, which consists of loss of signal energy, in a way that is directly proportional to the distance of the transmission and the frequency. This attenuation is measured in decibels lost per 100 m (dB / 100m). b) Crosstalk (apparent crossover) that occurs when the signal from a transmission line pair is filtered or connected to another adjacent pair and takes the form of noise. The generation of apparent crossover noise increases with increasing frequency, although the transmission in this apparent crossover stream along the adjacent pair is also subject to attenuation, measured in dB / 1000m, whose attenuation is It also increases with frequency. Therefore, there is a complex relationship between the generation and attenuation of the apparent crossing ruble with the increasing frequency. In a voice line, crosstalk (apparent crossover) is inconvenient, but in a line of data transmission is seriously disruptive, making the content and interpretation of the signal unreliable. Consequently, it is desirable to reduce its presence and effect to a minimum level. International standards have been established which enable the classification of electrical components into categories according to their performance against standardized values of attenuation and apparent crossing at different frequencies, and Category 5 is obtained if there is compatibility with standard loises at frequencies of up to 100 Hz. The known modules for connection and test of telephone lines, as described for example in E P-B-071 101 2, do not comply with the standards in question at such frequencies, and consequently, it is impossible in Those lines obtain the Category 5 classification currently required for the components of many transmission networks.

The Previous Technique does not provide a solution to this problem. US 4, 800, 463 for example, discloses barriers for mounting in a circuit board housing. The barriers prevent the user from inadvertently contacting exposed edge connectors or adjacent circuit boards. The barriers can be provided with a metallic coating for protection from electromagnetic interference. Document J P 09-180085 describes a protection box for protecting against high frequency signals in a test machine. The machine to be tested is placed in the protection box. The purpose of the present invention is to provide a module for connection and testing of transmission lines, which can operate at high frequencies of at least 100 MHz and which is compatible with the values attributed to attenuation and crosstalk in the standards which correspond to Category 5. The main concept for the functional effectiveness of this module consists of the separation of the adjacent modules in line connection boxes by incorporating metal shields connected to ground on one side of each module. Consequently, the design includes the means to establish the electrical continuity between the protective shield and the grounding electrode., which is obtained by means of a one-piece configuration, suitably formed by stamping (cutting and folding) the metal screen and the earth connection terminal. The effectiveness of the described solution has been analyzed in a laboratory, and it has been proved that the protected module complies with all the technical requirements necessary for its classification in Category 5, that is to say with operation at frequencies of at least 1 00 M Hz. In order to further illustrate the invention, the drawings of a specific embodiment are attached by way of example, which represent schematically different aspects of the shielded module. It's those drawings: Figure 1 is a perspective view of the shielded module, seen from the protected side of the metal shield; and Figure 2 is a perspective view of a single piece formed by the metal shield and the grounding terminal. Referring to the drawings, the module (3) is of the type described above in EP-B-071 1012 having connection means for forming connections to the line conductors, cutting means comprising a part of electrical continuity that is it can be extracted from the module, and circuit protection means connected to a grounding terminal (preferably by connection to the latter of a surrounding protective terminal) for protection against excessive voltages. The circuit protection means preferably comprises an ionized noble gas discharger. In preferred constructions, the circuit protection means is attached to, preferably trans- ported by, the portion of continuity that can be extracted from the module. Each module (3) includes a flat metallic screen (1) which is connected to ground and at least partially covers one of the sides of the module, to create a barrier against inductive effects between each two adjacent modules in a connection box. The electrical continuity between the protective shield and the grounding electrode is established by making the metal shield (1) and the grounding terminal (2) as one piece, for example by stamping and bending the sheet metal . The grounding terminal (2) is inserted (preferably encapsulated) into the body of the module, as is known per se from the existing modules, to make contact in use with the central grounding electrode (not shown). ) of the part of continuity that can be extracted, shown in those drawings with a knob or handle that projects upwards for the convenient manual disconnection of the circuits. Likewise, as is known per se, the metallic conductors (not shown) are connected to the wires that are inserted in the twin openings at each end of the link conductor module (not shown) in the continuity part, the which also holds a circuit protection gas discharge pipe (not shown) connected between the link conductors and the center ground connection electrode.

Claims (7)

1. CLAIMS 1. Module for connecting and testing high frequency transmission lines, which have connection means for forming connections to the line conductors, cutting means comprising a continuity part that can be extracted from the module, and circuit protection means connected to a ground terminal for protection against excessive voltages, characterized in that the module includes an electrically conductive shield connected to ground that covers one side of the module sufficiently to act as a barrier against the inductive effects between two or more such modules when they are placed adjacent to each other with the shield between them. Module according to claim 1, characterized in that the electrical continuity between the protective shield and the grounding electrode is established by forming them integrally, preferably as a single piece of metal. Module according to claim 2, characterized in that the shield is secured to the module at least partially by the insertion and retention of the grounding electrode in the module body and / or at least partially by clamping part of the module. module between the shield and the grounding electrode. 4. Module according to any preceding claim, characterized in that the shield is secured to the module by encapsulation. Module according to any preceding claim, characterized in that the shield is substantially flat. Module according to any preceding claim, characterized in that the circuit protection means comprise an ionized noble gas discharger. Module according to any preceding claim, characterized in that the circuit protection means are transported by the continuity part that can be extracted from the module.